JP2012131855A - Powdery and granular composition, heat-conductive pressure-sensitive adhesive composition, heat-conductive pressure-sensitive adhesive sheet-like molding, method for producing them, and electronic component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a powdery and granular composition which maintains the productivity of a heat-conductive pressure-sensitive adhesive composition or sheet-like molding, which conducts heat and is sensitive to pressure and adhesive, and, in particular, reduces heat resistance in the thickness direction: and to provide a heat-conductive pressure-sensitive adhesive composition and a sheet-like mold which conducts heat and is sensitive to pressure and adhesive which each contain the powdery and granular composition concerned; methods for producing them; and an electronic component having the heat-conductive pressure-sensitive adhesive composition or the sheet-like molding which conducts heat and is sensitive to pressure and adhesive.SOLUTION: The polymerization and crosslinking reactions of a (meth)acrylic acid ester monomer mixture in a mixture composition are carried out to gain a massive composition, and then the massive composition is pulverized to gain the powdery and granular composition, the mixture composition containing; a (meth)acrylic resin composition which contains a (meth)acrylic acid ester polymer and the (meth)acrylic acid ester monomer mixture; powdery expanded graphite having a particle size of >2 μm and <60 μm; and a polymerization initiator. The heat-conductive pressure-sensitive adhesive composition and the sheet-like molding, which conducts heat and is sensitive to pressure and adhesive, each contain the powdery and granular composition. The methods for producing them are provided here. The electronic component has the heat-conductive pressure-sensitive adhesive composition or the sheet-like molding which conducts heat and is sensitive to pressure and adhesive.

Description

  The present invention relates to a granular composition containing expanded graphite, a thermally conductive pressure-sensitive adhesive composition and a thermally conductive pressure-sensitive adhesive sheet-like molded article obtained by using the granular composition, and the granular form Composition, thermal conductive pressure-sensitive adhesive composition, method for producing thermal conductive pressure-sensitive adhesive sheet-like molded body, thermal conductive pressure-sensitive adhesive composition or thermal conductive pressure-sensitive adhesive sheet-like molding The present invention relates to an electronic component having a body.

  In recent years, electronic components such as plasma display panels (PDP), integrated circuit (IC) chips, and the like have increased in heat generation as their performance has increased. As a result, there is a need to take measures against functional failures due to temperature rise. In general, a method of dissipating heat by attaching a heat dissipator such as a metal heat sink, heat dissipating plate, heat dissipating fin or the like to a heat generating element such as an electronic component is employed. In order to efficiently conduct heat conduction from the heat generating body to the heat radiating body, various heat conducting sheets are used. In general, a heat conductive pressure-sensitive adhesive sheet-like molded body is required for use in fixing a heat generating body and a heat radiating body.

  The heat conductive pressure-sensitive adhesive sheet-like molded body is used as one of the purposes to transmit heat from the heat generating body to the heat radiating body, so that the thermal resistance of the heat conductive pressure-sensitive adhesive sheet-like molded body is lowered. It is preferable. In order to reduce the thermal resistance of the heat conductive pressure-sensitive adhesive sheet-like molded body, it is conceivable to add expanded graphite powder as in the techniques described in Patent Document 1 and Patent Document 2, for example.

JP 2010-144022 A JP 2007-16093 A

  According to the technique described in Patent Document 1, a thermally conductive pressure-sensitive adhesive sheet-like molded article comprising the resin composition is obtained by adding expanded graphite powder and a predetermined additive together with the resin composition. In addition, the expanded graphite powder can be uniformly dispersed in the surface direction of the thermally conductive pressure-sensitive adhesive sheet-like molded product, thereby reducing variations in physical properties. However, in the prior art, when a resin composition containing expanded graphite powder is formed into a sheet to obtain a heat conductive pressure-sensitive adhesive sheet-like molded body, the expanded graphite powder is easily oriented in the plane direction, In some cases, the effect of reducing the thermal resistance in the thickness direction of the pressure-sensitive adhesive sheet-like molded article becomes insufficient. In other words, heat is transmitted in the surface direction, but heat may be less transmitted in the thickness direction than in the surface direction. Moreover, in the technique described in patent document 2, although the expanded graphite powder was contained, the quantity was inadequate and the effect of reducing the thermal resistance of the composition obtained was inadequate. However, when a large amount of expanded graphite powder is added to the resin composition, there is a problem that the viscosity of the resin composition increases and it becomes difficult to form the resin composition into a sheet.

  Therefore, the present invention can reduce the thermal resistance, particularly in the thickness direction, while maintaining the productivity of the heat conductive pressure-sensitive adhesive composition or the heat conductive pressure-sensitive adhesive sheet-like molded product. A granular composition, a thermally conductive pressure-sensitive adhesive composition and a thermally conductive pressure-sensitive adhesive sheet-like molded article containing the granular composition, a production method thereof, and the thermally conductive pressure-sensitive adhesive composition or An object of the present invention is to provide an electronic component provided with the heat conductive pressure-sensitive adhesive sheet-like molded body. In the present invention, “productivity” means that a heat conductive pressure-sensitive adhesive composition or a heat conductive pressure-sensitive adhesive sheet-like molded body can be easily produced without causing cracks or cracks.

  As a result of continual research on the thermally conductive pressure-sensitive adhesive composition, the present inventors produced a granular composition having a predetermined size in which the expanded graphite powder is covered with a predetermined (meth) acrylic resin composition. And it discovered that the said subject could be solved by adding this granular composition to a predetermined | prescribed (meth) acrylic resin composition, and came to complete this invention.

  1st this invention forms (meth) acrylic acid which forms the homopolymer from which a (meth) acrylic acid ester polymer (AE1) is 5 mass% or more and 70 mass% or less, and a glass transition temperature is -20 degrees C or less. (Meth) acrylic resin composition (A1) containing (meth) acrylic acid ester monomer mixture (α1) 30% by mass or more and 95% by mass or less, containing an ester monomer as a main component and a polyfunctional monomer ) 100 parts by weight, expanded graphite powder having an average particle size of 2 μm or more and less than 60 μm (B) 100 parts by weight or more and 650 parts by weight or less, and a polymerization initiator (C1) 0.01 parts by weight or more and 10 parts by weight or less. It is the granular composition (D) formed by grind | pulverizing the block composition by which superposition | polymerization and crosslinking reaction of the said (meth) acrylic acid ester monomer mixture ((alpha) 1) in the mixed composition containing are performed.

  In the present invention, “(meth) acryl” means “acryl and / or methacryl”. In addition, “the main component is a (meth) acrylic acid ester monomer that forms a homopolymer having a glass transition temperature of −20 ° C. or lower” means a (meth) acrylic acid ester monomer mixture ( It means that 50 mass% or more of the (meth) acrylic acid ester monomer which forms the homopolymer from which the glass transition temperature will be -20 degrees C or less in the said mixture on the basis of (alpha) 1) whole. Moreover, in this invention, the average particle diameter of expanded graphite powder (B) or a granular composition (D) means what was measured by the method demonstrated below. That is, a laser type particle size measuring machine (manufactured by Seishin Enterprise Co., Ltd.) is used, and measurement is performed by a microsorting control method (a method in which the measurement target particles are allowed to pass only in the measurement region and the measurement reliability is improved). In this measurement method, the expanded graphite powder (B) or the granular composition (D) 0.01 g to 0.02 g to be measured flows in the cell, so that the expanded graphite powder flows into the measurement region. (B) or the powdered composition (D) is irradiated with semiconductor laser light having a wavelength of 670 nm, and the scattering and diffraction of the laser light at that time are measured with a measuring machine. The diameter and particle size distribution are calculated and the results are displayed.

  In the present invention, the particulate composition (D) is 95% by weight or more and has a particle size of 500 μm or less. All having a particle size of 500 μm or less are preferred. On the other hand, those having a particle size exceeding 5% by weight exceeding 500 μm are referred to as “bulk composition”.

  In the first aspect of the present invention, the (meth) acrylic acid ester monomer mixture (α1) is 90% by mass to 99.9% by mass of the (meth) acrylic acid ester monomer, and is multifunctional. It is preferable that 0.1 mass% or more and 10 mass% or less of monomers are included.

  The second aspect of the present invention is (meth) acrylic acid which forms a homopolymer having a (meth) acrylic acid ester polymer (AE2) of 5% by mass to 30% by mass and a glass transition temperature of −20 ° C. or less. (Meth) acrylic resin composition (A2) containing (meth) acrylic acid ester monomer mixture (α2) 70 mass% or more and 95 mass% or less containing an ester monomer as a main component and a polyfunctional monomer ) 100 parts by mass, 20 to 200 parts by mass of the granular composition (D) of the first invention of the present invention, and 0.01 to 10 parts by mass of a polymerization initiator (C2). It is a heat conductive pressure sensitive adhesive composition (E) in which the polymerization and crosslinking reaction of the (meth) acrylic acid ester monomer mixture (α2) in the mixed composition are performed.

  Here, “the main component is a (meth) acrylic acid ester monomer that forms a homopolymer having a glass transition temperature of −20 ° C. or lower” means a (meth) acrylic acid ester monomer mixture (α2) This means that the mixture contains 50% by mass or more of a (meth) acrylic acid ester monomer that forms a homopolymer having a glass transition temperature of −20 ° C. or lower in the mixture.

  The third aspect of the present invention is (meth) acrylic acid which forms a homopolymer having a (meth) acrylic acid ester polymer (AE2) of 5% by mass to 30% by mass and a glass transition temperature of −20 ° C. or less. (Meth) acrylic resin composition (A2) containing (meth) acrylic acid ester monomer mixture (α2) 70 mass% or more and 95 mass% or less containing an ester monomer as a main component and a polyfunctional monomer ) 100 parts by mass, 20 to 200 parts by mass of the granular composition (D) of the first invention of the present invention, and 0.01 to 10 parts by mass of a polymerization initiator (C2). After the mixture composition is formed into a sheet shape, or while the mixture composition is formed into a sheet shape, polymerization and crosslinking reaction of the (meth) acrylic acid ester monomer mixture (α2) is performed. Pressure-sensitive adhesive sheet-like molded product (F) It is.

  The fourth aspect of the present invention is (meth) acrylic acid which forms a homopolymer having a (meth) acrylic acid ester polymer (AE1) of 5% by mass to 70% by mass and a glass transition temperature of −20 ° C. or less. (Meth) acrylic resin composition (A1) containing (meth) acrylic acid ester monomer mixture (α1) 30% by mass or more and 95% by mass or less, containing an ester monomer as a main component and a polyfunctional monomer ) 100 parts by mass, expanded graphite powder having an average particle size of 2 m or more and less than 60 μm (B) 100 parts by mass or more and 650 parts by mass or less, and polymerization initiator (C1) 0.01 parts by mass or more and 10 parts by mass or less. After the mixing step, the mixing step, the step of polymerizing and crosslinking the (meth) acrylic acid ester monomer mixture (α1) to obtain a block composition, and the block composition into a powder Crushing step A method for producing a particulate composition (D).

  The fifth aspect of the present invention is (meth) acrylic acid which forms a homopolymer having a (meth) acrylic acid ester polymer (AE2) of 5% by mass to 30% by mass and a glass transition temperature of −20 ° C. or less. (Meth) acrylic resin composition (A2) containing (meth) acrylic acid ester monomer mixture (α2) 70 mass% or more and 95 mass% or less containing an ester monomer as a main component and a polyfunctional monomer ) 100 parts by mass, 20 parts by mass or more and 200 parts by mass or less of the granular composition (D) of the first invention, and 0.01 to 10 parts by mass of the polymerization initiator (C2). And a step of performing a polymerization reaction and a cross-linking reaction of the (meth) acrylic acid ester monomer mixture (α2) after the mixing step, and a mixing step for producing a mixed composition. It is a manufacturing method of an agent composition (E) .

  The sixth aspect of the present invention is (meth) acrylic acid which forms a homopolymer having a (meth) acrylic acid ester polymer (AE2) of 5% by mass to 30% by mass and a glass transition temperature of −20 ° C. or less. (Meth) acrylic resin composition (A2) containing (meth) acrylic acid ester monomer mixture (α2) 70 mass% or more and 95 mass% or less containing an ester monomer as a main component and a polyfunctional monomer ) 100 parts by mass, 20 parts by mass or more and 200 parts by mass or less of the granular composition (D) of the first invention, and 0.01 to 10 parts by mass of the polymerization initiator (C2). Then, after forming the mixed composition obtained in the mixing step and forming the mixed composition into a sheet shape, or while forming the mixed composition into a sheet shape, the (meth) acrylic Acid ester monomer mixture (α2) It is a manufacturing method of a heat conductive pressure-sensitive-adhesive sheet-like molded object (F) including the process of performing superposition | polymerization and crosslinking reaction.

  7th this invention was bonded to the heat radiator and the heat conductive pressure-sensitive-adhesive composition (E) of the said 2nd this invention bonded to this heat radiator, or a heat radiator and this heat radiator. It is an electronic component provided with the heat conductive pressure-sensitive-adhesive sheet-like molded object (F) of the said 3rd this invention.

  According to the first aspect of the present invention, while maintaining the productivity of the heat conductive pressure-sensitive adhesive composition or the heat conductive pressure-sensitive adhesive sheet-like molded product, their thermal resistance, particularly in the thickness direction, is reduced. Can be provided. That is, the powdered composition is mixed with a predetermined (meth) acrylic resin composition to obtain a mixed composition, which is used to form a heat conductive pressure-sensitive adhesive composition or a heat conductive pressure-sensitive adhesive sheet. By producing a molded body, it is possible to produce a heat conductive pressure-sensitive adhesive composition with reduced thermal resistance while maintaining productivity, or in particular heat with reduced thermal resistance in the thickness direction. A conductive pressure-sensitive adhesive sheet-like molded body can be produced.

  Moreover, the heat conductive pressure-sensitive-adhesive composition of 2nd this invention and the heat conductive pressure-sensitive-adhesive sheet-like molded object of 3rd this invention contain the granular composition of 1st this invention, Thermal resistance can be reduced while maintaining productivity during manufacturing. In particular, in the heat conductive pressure-sensitive adhesive sheet-like molded article of the third aspect of the present invention, the thermal resistance in the thickness direction can be reduced.

  Moreover, according to the manufacturing method of the granular composition of 4th this invention, the heat conductive pressure sensitive adhesive composition obtained from this mixed composition is used by mixing with a predetermined (meth) acrylic resin composition. The heat conductive pressure-sensitive adhesive composition or the heat conductive pressure-sensitive adhesive sheet-shaped molded body, particularly in the thickness direction, while maintaining the productivity of the product or the heat-conductive pressure-sensitive adhesive sheet-shaped molded body A granular composition that can reduce the resistance can be produced.

  Moreover, according to the manufacturing method of the heat conductive pressure sensitive adhesive composition of 5th this invention, the heat conductive pressure sensitive adhesive by which heat resistance was reduced by using the granular composition of 1st this invention. The composition can be easily produced.

  Moreover, according to the manufacturing method of the heat conductive pressure-sensitive-adhesive sheet-like molded body of the sixth aspect of the present invention, the thermal resistance in the thickness direction is particularly reduced by using the granular composition of the first aspect of the present invention. In addition, the heat conductive pressure-sensitive adhesive sheet-like molded body can be easily produced.

  In addition, according to the seventh aspect of the present invention, by providing the heat conductive pressure-sensitive adhesive composition of the second aspect of the present invention or the heat conductive pressure-sensitive adhesive sheet-like molded body of the third aspect of the present invention, to the heat radiating body. It is possible to provide an electronic component that can easily transfer heat and has improved heat dissipation.

1. Powdered composition (D)
The granular composition (D) of the present invention forms a homopolymer having a (meth) acrylic acid ester polymer (AE1) of 5% by mass to 70% by mass and a glass transition temperature of −20 ° C. or less. (Meth) acrylic acid containing (meth) acrylic acid ester monomer as a main component and (meth) acrylic acid ester monomer mixture (α1) 30% by mass to 95% by mass including a polyfunctional monomer 100 parts by mass of the resin composition (A1), 100 parts by mass or more and 650 parts by mass or less of the expanded graphite powder (B) having an average particle size of 2 μm or more and less than 60 μm, and 0.01 parts by mass or more and 10 parts by mass or more of the polymerization initiator (C1). The bulk composition formed by polymerization and crosslinking reaction of the (meth) acrylic acid ester monomer mixture (α1) in a mixed composition containing a part or less is pulverized. The substance contained in the granular composition (D) will be described below.

<(Meth) acrylic resin composition (A1)>
The (meth) acrylic resin composition (A1) used in the present invention is a (meth) acrylic acid ester polymer (AE1) and a (meth) acrylic that forms a homopolymer having a glass transition temperature of −20 ° C. or lower. A (meth) acrylic acid ester monomer mixture (α1) containing an acid ester monomer (a5m) as a main component and a polyfunctional monomer (a6m) is included. In addition, as mentioned above, when obtaining the block composition which is a precursor of a granular composition (D), superposition | polymerization and crosslinking reaction of a (meth) acrylic acid ester monomer mixture ((alpha) 1) are performed. By performing the polymerization and crosslinking reaction, the polymer of the (meth) acrylic acid ester monomer mixture (α1) is mixed and / or partially bonded to the component of the (meth) acrylic acid ester polymer (AE1).

  In the present invention, the amount of the (meth) acrylic acid ester polymer (AE1) and the (meth) acrylic acid ester monomer mixture (α1) contained in the (meth) acrylic resin composition (A1) is (meth) With respect to 100% by mass of the acrylic resin composition (A1), the (meth) acrylic acid ester polymer (AE1) is 5% by mass to 70% by mass, and the (meth) acrylic acid ester monomer mixture (α1) is 30%. The mass is 95% by mass or more. When the content ratio of the (meth) acrylic acid ester monomer mixture (α1) is 30% by mass or more and 95% by mass or less, the sol viscosity of the mixed composition at the time of mixing is suppressed to be low, and the productivity is excellent. The conductive pressure-sensitive adhesive sheet-like molded article is excellent in shape followability and tackiness. If it is less than 30% by mass, the sol viscosity during mixing is high and mixing is difficult. On the other hand, when it exceeds 95% by mass, the granular composition (D) tends to be difficult to fix the shape of the expanded graphite powder (B).

((Meth) acrylic acid ester polymer (AE1))
The (meth) acrylic acid ester polymer (AE1) that can be used in the present invention is not particularly limited, but the (meth) acrylic acid ester monomer that forms a homopolymer having a glass transition temperature of −20 ° C. or lower. It is preferable to contain the unit (a1) and the monomer unit (a2) having an organic acid group.

  The (meth) acrylic acid ester monomer (a1m) which gives the unit (a1) of the (meth) acrylic acid ester monomer is not particularly limited. For example, ethyl acrylate (the glass transition temperature of the homopolymer is -24 ° C), n-propyl acrylate (-37 ° C), n-butyl acrylate (-54 ° C), sec-butyl acrylate (-22 ° C), n-heptyl acrylate (- 60 ° C), n-hexyl acrylate (-61 ° C), n-octyl acrylate (-65 ° C), 2-ethylhexyl acrylate (-50 ° C), 2-methoxyethyl acrylate (-50) ° C), 3-methoxypropyl acrylate (-75 ° C), 3-methoxybutyl acrylate (-56 ° C), n-octyl methacrylate (-25 ° C), n-decyl methacrylate (-49) ), And the like. Among these, n-butyl acrylate, 2-ethylhexyl acrylate, and 2-methoxyethyl acrylate are preferable, n-butyl acrylate and 2-ethylhexyl acrylate are more preferable, and 2-ethylhexyl acrylate is more preferable.

  These (meth) acrylic acid ester monomers (a1m) may be used individually by 1 type, and may use 2 or more types together.

  The monomer unit (a1) derived from the (meth) acrylic acid ester monomer (a1m) is preferably 80% by mass or more and 99.9% by mass in the (meth) acrylic acid ester polymer (AE1). Hereinafter, it is used in the polymerization in such an amount that it is more preferably 85% by mass or more and 99.5% by mass or less. When the amount of the (meth) acrylic acid ester monomer (a1m) is within the above range, the viscosity of the polymerization system at the time of polymerization can be maintained within an appropriate range.

  The monomer (a2m) that gives the monomer unit (a2) having the organic acid group is not particularly limited, but representative examples thereof include organic acid groups such as a carboxyl group, an acid anhydride group, and a sulfonic acid group. The monomer which has can be mentioned. In addition to these, monomers containing sulfenic acid groups, sulfinic acid groups, phosphoric acid groups, and the like can also be used.

  Specific examples of the monomer having a carboxyl group include, for example, α, β-ethylenically unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid, and α, such as itaconic acid, maleic acid, and fumaric acid. In addition to β-ethylenically unsaturated polyvalent carboxylic acid, α, β-ethylenically unsaturated polyvalent carboxylic acid partial esters such as monomethyl itaconate, monobutyl maleate and monopropyl fumarate can be used. Moreover, what has group which can be induced | guided | derived to a carboxyl group by hydrolysis etc., such as maleic anhydride and itaconic anhydride, can be used similarly.

  Specific examples of the monomer having a sulfonic acid group include allyl sulfonic acid, methallyl sulfonic acid, vinyl sulfonic acid, styrene sulfonic acid, α, β-unsaturated sulfonic acid such as acrylamide-2-methylpropane sulfonic acid, And salts thereof.

  As the monomer (a2m), among the monomers having an organic acid group exemplified above, a monomer having a carboxyl group is more preferable, and a monomer having acrylic acid or methacrylic acid is particularly preferable. . These monomers are industrially inexpensive and can be easily obtained, have good copolymerizability with other monomer components, and are preferable in terms of productivity. In addition, a monomer (a2m) may be used individually by 1 type, and may use 2 or more types together.

  In the monomer (a2m) having an organic acid group, the monomer unit (a2) derived therefrom is 0.1% by mass or more and 20% by mass or less in the (meth) acrylic acid ester polymer (AE1), preferably It is desirable to be used for the polymerization in such an amount that it is 0.5 mass% or more and 15 mass% or less. When the usage-amount of the monomer (a2m) which has an organic acid group exists in the said range, the viscosity of the polymerization system at the time of superposition | polymerization can be maintained in an appropriate range.

  The monomer unit (a2) having an organic acid group is introduced into the (meth) acrylic acid ester polymer (AE1) by polymerization of the monomer (a2m) having an organic acid group as described above. Although it is simple and preferable, an organic acid group may be introduced by a known polymer reaction after the (meth) acrylic acid ester polymer (AE1) is formed.

  The (meth) acrylic acid ester polymer (AE1) may contain a monomer unit (a3) derived from a monomer (a3m) having a functional group other than an organic acid group.

  Examples of the functional group other than the organic acid group include a hydroxyl group, an amino group, an amide group, an epoxy group, and a mercapto group.

  Examples of the monomer having a hydroxyl group include (meth) acrylic acid hydroxyalkyl esters such as (meth) acrylic acid 2-hydroxyethyl and (meth) acrylic acid 3-hydroxypropyl.

  Examples of the monomer having an amino group include N, N-dimethylaminomethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, and aminostyrene.

  Examples of monomers having an amide group include α, β-ethylenically unsaturated carboxylic acid amide monomers such as acrylamide, methacrylamide, N-methylol acrylamide, N-methylol methacrylamide, and N, N-dimethylacrylamide. Can be mentioned.

  Examples of the monomer having an epoxy group include glycidyl (meth) acrylate and allyl glycidyl ether.

  As the monomer (a3m) having a functional group other than the organic acid group, one type may be used alone, or two or more types may be used in combination.

  In the monomer (a3m) having a functional group other than these organic acid groups, the monomer unit (a3) derived therefrom is 10% by mass or less in the (meth) acrylate polymer (AE1). It is preferred to be used in the polymerization in such an amount. By using 10 mass% or less of monomer (a3m), the viscosity of the polymerization system at the time of polymerization can be maintained in an appropriate range.

  The (meth) acrylic acid ester polymer (AE1) has a (meth) acrylic acid ester monomer unit (a1) that forms a homopolymer having the above-described glass transition temperature of −20 ° C. or lower, and an organic acid group. In addition to the monomer unit (a2) and the monomer unit (a3) having a functional group other than an organic acid group, a monomer derived from the monomer (a4m) copolymerizable with the above-described monomer. The monomer unit (a4) may be contained. A monomer (a4m) may be used individually by 1 type, and may use 2 or more types together.

  The amount of the monomer unit (a4) derived from the monomer (a4m) is preferably 10% by mass or less, more preferably 5% by mass or less, based on the acrylate polymer (AE1).

  The monomer (a4m) is not particularly limited, and specific examples thereof include (meth) acrylate monomers other than the (meth) acrylate monomer (a1m), α, β-ethylenic monomers. Saturated polyvalent carboxylic acid complete ester, alkenyl aromatic monomer, conjugated diene monomer, vinyl cyanide monomer, carboxylic acid unsaturated alcohol ester, olefin monomer and the like can be mentioned.

  Specific examples of the (meth) acrylate monomer other than the (meth) acrylate monomer (a1m) include methyl acrylate (homopolymer having a glass transition temperature of 10 ° C.), methyl methacrylate. (105 ° C.), ethyl methacrylate (63 ° C.), n-propyl methacrylate (25 ° C.), and n-butyl methacrylate (20 ° C.).

  Specific examples of the α, β-ethylenically unsaturated polyvalent carboxylic acid complete ester include dimethyl fumarate, diethyl fumarate, dimethyl maleate, diethyl maleate, dimethyl itaconate and the like.

  Specific examples of the alkenyl aromatic monomer include styrene, α-methylstyrene, methyl α-methylstyrene, vinyltoluene and the like.

  Specific examples of the conjugated diene monomer include 1,3-butadiene, 2-methyl-1,3-butadiene (synonymous with isoprene), 1,3-pentadiene, and 2,3-dimethyl-1,3-butadiene. , 2-chloro-1,3-butadiene, cyclopentadiene, and the like.

  Specific examples of the vinyl cyanide monomer include acrylonitrile, methacrylonitrile, α-chloroacrylonitrile, α-ethylacrylonitrile and the like.

  Specific examples of the carboxylic acid unsaturated alcohol ester monomer include vinyl acetate.

  Specific examples of the olefin monomer include ethylene, propylene, butene, pentene and the like.

  The weight average molecular weight (Mw) of the (meth) acrylic acid ester polymer (AE1) is measured by gel permeation chromatography (GPC method) and is in the range of 100,000 to 1,000,000 in terms of standard polystyrene. It is more preferable that it is in the range of 200,000 or more and 500,000 or less.

  The (meth) acrylic acid ester polymer (AE1) is a (meth) acrylic acid ester monomer (a1m), a monomer having an organic acid group, which forms a homopolymer having a glass transition temperature of −20 ° C. or lower. (A2m), a monomer containing a functional group other than an organic acid group (a3m) used as required, and a monomer copolymerizable with these monomers used as needed ( a4m) can be obtained particularly preferably by copolymerization.

  The polymerization method is not particularly limited, and may be any of solution polymerization, emulsion polymerization, suspension polymerization, bulk polymerization and the like, and may be other methods. Solution polymerization is preferred, and among them, solution polymerization using a carboxylic acid ester such as ethyl acetate or ethyl lactate or an aromatic solvent such as benzene, toluene or xylene as the polymerization solvent is more preferred. In the polymerization, the monomer may be added in portions to the polymerization reaction vessel, but it is preferable to add the whole amount at once. The method for initiating the polymerization is not particularly limited, but it is preferable to use a thermal polymerization initiator as the polymerization initiator. The thermal polymerization initiator is not particularly limited, and may be either a peroxide or an azo compound.

  Peroxide polymerization initiators include hydroperoxides such as t-butyl hydroperoxide, peroxides such as benzoyl peroxide and cyclohexanone peroxide, and persulfates such as potassium persulfate, sodium persulfate and ammonium persulfate. Can be mentioned. These peroxides can also be used as a redox catalyst in appropriate combination with a reducing agent.

  As the azo compound polymerization initiator, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (2-methylbutyronitrile) And so on.

  Although the usage-amount of a polymerization initiator is not specifically limited, It is preferable that it is the range of 0.01 mass part or more and 50 mass parts or less with respect to 100 mass parts of monomers.

  Other polymerization conditions (polymerization temperature, pressure, stirring conditions, etc.) of these monomers are not particularly limited.

  After completion of the polymerization reaction, the obtained polymer is separated from the polymerization medium as necessary. The separation method is not particularly limited. In the case of solution polymerization, the (meth) acrylic acid ester polymer (AE1) can be obtained by placing the polymerization solution under reduced pressure and distilling off the polymerization solvent.

  The weight average molecular weight of the (meth) acrylic acid ester polymer (AE1) can be controlled by appropriately adjusting the amount of the polymerization initiator used in the polymerization and the amount of the chain transfer agent.

((Meth) acrylic acid ester monomer mixture (α1))
The (meth) acrylic acid ester monomer mixture (α1) is mainly composed of a (meth) acrylic acid ester monomer (a5m) that forms a homopolymer having a glass transition temperature of −20 ° C. or lower. Sex monomer (a6m) is included. As described above, the above “main component” means “containing 50% by mass or more”.

  In addition, the (meth) acrylic acid ester monomer mixture (α1) is 90% by mass or more and 99.9% by mass or less of the (meth) acrylic acid ester monomer (a5m), and a polyfunctional monomer ( a6m) It is preferable that 0.1 mass% or more and 10 mass% or less are included. When the content ratio of the (meth) acrylic acid ester monomer (a5m) is 90% by mass or more and 99.9% by mass or less, the heat conductive pressure-sensitive adhesive composition (E) and the heat conductive pressure sensitive of the present invention. The adhesive sheet-like molded product (F) is excellent in tackiness and has low thermal resistance (excellent in the cool-down effect).

  As a (meth) acrylic acid ester monomer (a5m) that forms a homopolymer having a glass transition temperature of −20 ° C. or lower, for example, ethyl acrylate (the glass transition temperature of the homopolymer is −24 ° C.) , N-propyl acrylate (-37 ° C), n-butyl acrylate (-54 ° C), sec-butyl acrylate (-22 ° C), n-heptyl acrylate (-60 ° C), acrylic N-hexyl acid (-61 ° C), n-octyl acrylate (-65 ° C), 2-ethylhexyl acrylate (-50 ° C), 2-methoxyethyl acrylate (-50 ° C), acrylic acid Examples include 3-methoxypropyl (same as -75 ° C.), 3-methoxybutyl acrylate (same as −56 ° C.), n-octyl methacrylate (same as −25 ° C.), and n-decyl methacrylate (same as −49 ° C.). It is possible. Among these, n-butyl acrylate, 2-ethylhexyl acrylate, and 2-methoxyethyl acrylate are more preferable, n-butyl acrylate and 2-ethylhexyl acrylate are more preferable, and 2-ethylhexyl acrylate is particularly preferable. The said (meth) acrylic acid ester monomer (a5m) may be used individually by 1 type, and may use 2 or more types together.

  As the polyfunctional monomer (a6m), a polyfunctional monomer copolymerizable with the (meth) acrylic acid ester monomer (a5m) is used. By copolymerizing the polyfunctional monomer (a6m), intramolecular and / or intermolecular crosslinking can be introduced into the (meth) acrylic resin composition (A1). In the process of producing a heat conductive pressure-sensitive adhesive composition or a heat conductive pressure-sensitive adhesive sheet-like molded article using the product (D), the expanded graphite powder (B) was coated with a (meth) acrylic resin composition. It is assumed that the state can be maintained.

  Examples of the polyfunctional monomer (a6m) include 1,6-hexanediol di (meth) acrylate, 1,2-ethylene glycol di (meth) acrylate, 1,12-dodecanediol di (meth) acrylate, Polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, Multifunctional (meth) acrylates such as ditrimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and 2,4-bis ( Other substituted triazines, such as Rikuroromechiru) -6-p-methoxystyrene-5-triazine, etc. monoethylenically unsaturated aromatic ketones such as 4-acryloxy benzophenone can be used. Among these, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, and pentaerythritol tetra (meth) acrylate are preferable. A polyfunctional monomer (a6m) may be used individually by 1 type, and may use 2 or more types together.

  The (meth) acrylic acid ester monomer mixture (α1) is a monomer having an organic acid group that can be copolymerized with the (meth) acrylic acid ester monomer (a5m) or the polyfunctional monomer (a6m). It may contain a monomer (a7m). Examples of the monomer (a7m) having an organic acid group include monomers having the same organic acid group as those exemplified as the monomer (a2m), and thus the description thereof is omitted. . As the monomer having an organic acid group (a7m), one type may be used alone, or two or more types may be used in combination.

  The monomer (a7m) is preferably used in the polymerization in such an amount that it is 9.9% by mass or less in the (meth) acrylic acid ester monomer mixture (α1). By using the 9.9 monomer (a7m), the viscosity of the mixed composition at the time of polymerization can be maintained in an appropriate range.

  In addition, the (meth) acrylic acid ester monomer mixture (α1) is another monomer copolymerizable with the above-described monomers contained in the (meth) acrylic acid ester monomer mixture (α1) ( a8m) may be contained. Examples of the monomer (a8m) include the same monomers as those exemplified as the monomer (a3m) and the monomer (a4m), and thus the description thereof is omitted. A monomer (a8m) may be used individually by 1 type, and may use 2 or more types together.

  The monomer (a8m) is preferably used in the polymerization in such an amount that it is 9.9% by mass or less in the (meth) acrylic acid ester monomer mixture (α1). By using a 9.9 mass% or less monomer (a8m), the viscosity of the mixed composition at the time of superposition | polymerization can be maintained in an appropriate range.

<Expanded graphite powder (B) having an average particle size of 2 μm or more and less than 60 μm>
As an example of the expanded graphite powder (B) used in the present invention, the acid-treated graphite is heat-treated at 500 ° C. or more and 1200 ° C. or less to expand to 100 ml / g or more and 300 ml / g or less, and then pulverized. The thing obtained through the process of including can be mentioned. More preferably, the graphite is treated with a strong acid, sintered in an alkali, and then treated again with a strong acid at a temperature of 500 ° C. or higher and 1200 ° C. or lower to remove the acid and at least 100 ml / g to 300 ml / g. What was obtained through the process including expansion | swelling below and then grind | pulverizing can be mentioned below. The temperature of the heat treatment is particularly preferably 800 ° C. or higher and 1000 ° C. or lower.

  The average particle size of the expanded graphite powder (B) used in the present invention is 2 μm or more and less than 60 μm. The upper limit of the average particle size of the expanded graphite powder (B) is preferably 50 μm, and more preferably 40 μm. On the other hand, the lower limit of the average particle size of the expanded graphite powder (B) is preferably 2.5 μm, and more preferably 3 μm. By setting the average particle size of the expanded graphite powder (B) to 2 μm or more and less than 60 μm, when the bulk composition is produced as described later, the bulk composition is made into a powdery composition (D). Can be easily done. In addition, as mentioned above, “powder” means that 95% by weight or more has a particle size of 500 μm or less. All having a particle size of 500 μm or less are preferred. When the average particle diameter of the expanded graphite powder (B) is less than 2 μm, the heat resistance of the heat conductive pressure-sensitive adhesive composition (E) or the heat conductive pressure-sensitive adhesive sheet-like molded body (F) described later is reduced. There is a risk that it will become large (the cool-down effect will be poor). In addition, the term “agglomerated” refers to those having a particle size exceeding 500 μm and exceeding 5% by weight. When producing a heat conductive pressure-sensitive adhesive sheet-like molded product, if the mixed composition constituting the heat-contained composition contains a “bulk composition”, the heat conductive pressure-sensitive adhesive having a desired thickness There is a possibility that the sheet-like molded body cannot be molded. On the other hand, by setting the average particle size of the expanded graphite powder (B) to less than 60 μm, the thermally conductive pressure-sensitive adhesive composition (E) or When manufacturing a heat conductive pressure-sensitive-adhesive sheet-like molded object (F), it becomes easy to shape | mold a heat conductive pressure-sensitive-adhesive composition (E) or a heat conductive pressure-sensitive-adhesive sheet-like molded object (F). .

  Content of the expanded graphite powder (B) used for this invention is 100 mass parts or more and 650 mass parts or less with respect to 100 mass parts of (meth) acrylic resin composition (A1). The upper limit of the content of the expanded graphite powder (B) is preferably 500 parts by mass, and more preferably 400 parts by mass. On the other hand, 150 mass parts is preferable and, as for the minimum of content of expanded graphite powder (B), 250 mass parts is more preferable. When the content of the expanded graphite powder (B) is less than 100 parts by mass, the thermal resistance of the granular composition (D) tends to increase (inferior in the cool-down effect). On the other hand, when the content of the expanded graphite powder (B) is more than 650 parts by mass, the expanded graphite powder (B) is coated with the (meth) acrylic resin composition even if the granular composition (D) is to be produced. There is a possibility that an unthinned composition is formed. When the said composition is used, it will become difficult to manufacture the heat conductive pressure sensitive adhesive composition (E) demonstrated later or a heat conductive pressure sensitive adhesive sheet-like molded object (F).

<Polymerization initiator (C1)>
When the powder composition (D) is molded, the (meth) acrylic acid ester monomer mixture (α1) is polymerized. In order to accelerate the polymerization, the mixed composition constituting the particulate composition (D) contains a polymerization initiator (C1).

  Examples of the polymerization initiator (C1) that can be used in the present invention include a photopolymerization initiator, an azo thermal polymerization initiator, an organic peroxide thermal polymerization initiator, and the like. An organic peroxide thermal polymerization initiator is preferably used from the viewpoint of allowing the polymerization to proceed rapidly even underneath.

  Various known photopolymerization initiators can be used as the photopolymerization initiator. Of these, acylphosphine oxide compounds are preferred. Examples of the acylphosphine oxide compound that is a preferred photopolymerization initiator include bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide and 2,4,6-trimethylbenzoyldiphenylphosphine oxide.

  As the azo thermal polymerization initiator, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (2-methylbutyronitrile) ) And the like.

  As the organic peroxide thermal polymerization initiator, hydroperoxide such as t-butyl hydroperoxide, benzoyl peroxide, cyclohexanone peroxide, 1,6-bis (t-butylperoxycarbonyloxy) hexane, 1,1-bis ( Examples thereof include peroxides such as (t-butylperoxy) -3,3,5-trimethylcyclohexanone, but it is preferable not to release volatile substances that cause odor during thermal decomposition. Among organic peroxide thermal polymerization initiators, those having a one-minute half-life temperature of 100 ° C. or more and 170 ° C. or less are preferable.

  Content of a polymerization initiator (C1) is 0.01 mass part or more and 10 mass parts or less with respect to 100 mass parts of (meth) acrylic resin compositions (A1). As for the minimum of the usage-amount of a polymerization initiator (C1), 0.1 mass part is preferable and 0.3 mass part is more preferable. On the other hand, the upper limit of the amount of the polymerization initiator (C1) used is preferably 5 parts by mass and more preferably 2 parts by mass. The polymerization conversion rate of the (meth) acrylic acid ester monomer mixture (α1) is preferably 95% by mass or more. By setting the content of the polymerization initiator (C1) to 0.01 parts by mass or more and 10 parts by mass or less, the polymerization conversion rate of the (meth) acrylic acid ester monomer mixture (α1) can be within an appropriate range. it can. If content of a polymerization initiator (C1) is less than 0.01 mass part, the polymerization conversion rate of a (meth) acrylic acid ester monomer mixture ((alpha) 1) will become low, and the granular composition (D) demonstrated later ) May leave a monomer odor. Moreover, when the usage-amount of a polymerization initiator (C1) exceeds 10 mass parts, what has extremely low molecular weight will generate | occur | produce in the polymer of a (meth) acrylic acid ester monomer mixture ((alpha) 1), and it will be granular There exists a possibility that a composition (D) may not be obtained as a granular form.

  By producing the granular composition (D) of the present invention as described later, a heat conductive pressure-sensitive adhesive composition (E) or a heat conductive pressure-sensitive adhesive sheet-like molded body (F) described later. It is possible to obtain a particle size suitable for addition to the mixed composition that constitutes. And the heat conductive pressure sensitive adhesive by including the granular composition (D) of this invention in a heat conductive pressure sensitive adhesive composition (E) or a heat conductive pressure sensitive adhesive sheet-like molded object (F). Especially the thermal resistance of the thickness direction of an agent composition (E) or a heat conductive pressure-sensitive-adhesive sheet-like molded object (F) can be reduced. This is presumed to be due to the following reason.

  As described above, according to the prior art, when a resin composition containing expanded graphite powder is formed into a sheet to obtain a heat conductive pressure-sensitive adhesive sheet-like molded body, the expanded graphite powder is oriented in the plane direction. In some cases, the effect of reducing the thermal resistance in the thickness direction of the heat-conductive pressure-sensitive adhesive sheet-like molded article is insufficient. In other words, heat is transmitted in the surface direction, but heat may be less transmitted in the thickness direction than in the surface direction. This is because when the resin composition is made into a sheet, a force acts in the surface direction of the sheet, so that the longitudinal direction of the expanded graphite powder (the longest direction of the expanded graphite powder) is relative to the surface direction of the sheet. This is presumably because the direction is close to parallel. On the other hand, the granular composition (D) of the present invention is an expanded graphite powder (B) that is not coated by coating the expanded graphite powder (B) with a crosslinked (meth) acrylic resin composition. Therefore, when the resin composition containing the granular composition (D) is formed into a sheet, the longitudinal direction of the granular composition (D) is relative to the surface direction of the sheet. It is presumed that it is difficult to face in a direction close to parallel, in other words, it is easier to face in the thickness direction.

  Further, as described above, when a large amount of expanded graphite powder is added to the resin composition, there is a problem that the viscosity of the resin composition increases and it becomes difficult to form the resin composition into a sheet. This is presumed to be because when the expanded graphite powder is mixed with the resin composition, the resin composition is taken into the gap of the expanded graphite powder. On the other hand, since the expanded graphite powder (B) is coated with the (meth) acrylic resin composition, the granular composition (D) of the present invention is mixed with the resin composition. It is presumed that the resin composition is difficult to be taken into the granular composition (D). Therefore, even if it mixes a granular composition (D) with a resin composition in large quantities, it is guessed that the viscosity of this resin composition does not increase easily and can make this resin composition into a sheet easily.

2. Production method of powder composition (D) The powder composition (D) of the present invention is prepared by mixing the materials described above, and then polymerizing and crosslinking the (meth) acrylic acid ester monomer mixture (α1). The bulk composition obtained by the reaction can be obtained by pulverization.

  That is, the method for producing the granular composition (D) of the present invention is a single (meth) acrylic acid ester polymer (AE1) of 5% by mass to 70% by mass and a glass transition temperature of −20 ° C. or less. A (meth) acrylic acid ester monomer mixture (α1) having a (meth) acrylic acid ester monomer that forms a polymer as a main component and containing a polyfunctional monomer is 30% by mass to 95% by mass. 100 parts by mass of the (meth) acrylic resin composition (A1) to be contained, 100 parts by mass to 650 parts by mass of expanded graphite powder having an average particle size of 2 μm to less than 60 μm, and 0.01 parts by mass or more of the polymerization initiator (C1) A mixing step of mixing 10 parts by mass or less, a step of polymerizing and crosslinking the (meth) acrylic acid ester monomer mixture (α1) after the mixing step to obtain a block composition, and the block Granule composition A step of pulverizing the. In addition, the preferable content ratio of each material is as above-mentioned, and description is abbreviate | omitted. In addition, it is preferable to heat the polymerization and crosslinking reaction of the (meth) acrylic acid ester monomer mixture (α1). For the heating, for example, hot air, an electric heater, infrared rays, or the like can be used. The heating temperature at this time is preferably a temperature at which the polymerization initiator (C1) is efficiently decomposed and the polymerization and crosslinking reaction of the (meth) acrylic acid ester monomer mixture (α1) proceeds. Although the range of the said heating temperature changes with kinds of polymerization initiator (C1) to be used, 100 to 200 degreeC is preferable and 130 to 180 degreeC is more preferable.

  There is no particular limitation on the method of pulverizing the massive composition. For example, manual pulverization using a rod or hammer, pulverization using a desktop hammer type fine pulverizer, pulverization using a knife hammer type crushing and sizing machine, pulverization using a fine pulverizer with built-in impact type classifier Pulverization by compression by passing through a roll, pulverization by compression using a press machine, and the like.

3. Thermally conductive pressure-sensitive adhesive composition (E) and thermally conductive pressure-sensitive adhesive sheet-like molded body (F)
The heat conductive pressure-sensitive adhesive composition (E) of the present invention has a (meth) acrylic acid ester polymer (AE2) of 5% by mass to 30% by mass and a single weight having a glass transition temperature of −20 ° C. or less. (Meth) acrylic acid ester monomer that forms a coalescence as a main component, and (meth) acrylic acid ester monomer mixture (α2) containing a polyfunctional monomer (70% by mass to 95% by mass) 100 parts by weight of the (meth) acrylic resin composition (A2), 20 parts by weight to 200 parts by weight of the granular composition (D) of the present invention, and 0.01 parts by weight to 10 parts by weight of the polymerization initiator (C2). Polymerization and crosslinking reaction of the (meth) acrylic acid ester monomer mixture (α2) in a mixed composition comprising: Moreover, the heat conductive pressure-sensitive-adhesive sheet-like molded object (F) of this invention is (meth) acrylic acid after shape | molding the said mixed composition in a sheet form, or shape | molding the said mixed composition in a sheet form. The ester monomer mixture (α2) is polymerized and crosslinked. The main substances contained in the heat conductive pressure-sensitive adhesive composition (E) and the heat conductive pressure-sensitive adhesive sheet-like molded body (F) will be described below.

<(Meth) acrylic resin composition (A2)>
The (meth) acrylic resin composition (A2) used in the present invention is a (meth) acrylic acid ester polymer (AE2) and a (meth) acrylic that forms a homopolymer having a glass transition temperature of −20 ° C. or lower. A (meth) acrylic acid ester monomer mixture (α2) containing an acid ester monomer as a main component and a polyfunctional monomer is included. In addition, as mentioned above, when obtaining a heat conductive pressure sensitive adhesive composition (E) and a heat conductive pressure sensitive adhesive sheet-like molded object (F), (meth) acrylic acid ester monomer mixture ((alpha) 2). Polymerization and cross-linking reaction are carried out. By performing the polymerization and the crosslinking reaction, the polymer of the (meth) acrylic acid ester monomer mixture (α2) is mixed and / or partially bonded to the component of the (meth) acrylic acid ester polymer (AE2).

  In the present invention, the amount of the acrylic acid ester polymer (AE2) and the (meth) acrylic acid ester monomer mixture (α2) contained in the (meth) acrylic resin composition (A2) is the (meth) acrylic resin composition. (Meth) acrylic acid ester polymer (AE2) 5% by mass to 30% by mass and (meth) acrylic acid ester monomer mixture (α2) 70% by mass to 95% by mass with respect to 100% by mass of product (A2). % Or less is preferable. By making these content ratio into the said range, the moldability of a heat conductive pressure sensitive adhesive composition (E) and a heat conductive pressure sensitive adhesive sheet-like molded object (F) becomes favorable.

((Meth) acrylic acid ester polymer (AE2))
As the (meth) acrylic acid ester polymer (AE2) that can be used in the present invention, the same (meth) acrylic acid ester polymer (AE1) as described above can be used. That is, the (meth) acrylic acid ester polymer (AE2) is a (meth) acrylic acid ester monomer unit (a1) that forms a homopolymer having a glass transition temperature of −20 ° C. or lower, and an organic acid. It preferably contains a monomer unit (a2) having a group.

  Specific examples of the (meth) acrylate monomer (a1m) giving the unit (a1) of the (meth) acrylate monomer that forms a homopolymer having a glass transition temperature of −20 ° C. or less are described above. The (meth) acrylic acid ester monomer (a1m) may be used alone or in combination of two or more. Further, in the (meth) acrylate monomer (a1m), the monomer unit (a1) derived therefrom is preferably 80% by mass or more and 99.9% in the (meth) acrylate polymer (AE2). It is used for the polymerization in an amount of not more than mass%, more preferably not less than 85 mass% and not more than 99.5 mass%. When the amount of the (meth) acrylic acid ester monomer (a1m) is within the above range, the viscosity of the polymerization system at the time of polymerization can be maintained within an appropriate range.

  Specific examples of the monomer (a2m) that gives the monomer unit (a2) having the organic acid group are as described above, and the monomer (a2m) may be used alone. Two or more kinds may be used in combination. The monomer (a2m) has a monomer unit (a2) derived therefrom in the (meth) acrylic acid ester polymer (AE2) of 0.1% by mass to 20% by mass, preferably 0.5%. It is desirable to be used for the polymerization in such an amount that it is from 15% by weight to 15% by weight. When the usage-amount of the monomer (a2m) which has an organic acid group exists in the said range, the viscosity of the polymerization system at the time of superposition | polymerization can be maintained in an appropriate range.

  The monomer unit (a2) having an organic acid group can be easily introduced into the (meth) acrylate polymer (AE2) by polymerization of the monomer (a2m) having an organic acid group. Although it is preferable, an organic acid group may be introduced by a known polymer reaction after the (meth) acrylic acid ester polymer (AE2) is formed.

  Moreover, the (meth) acrylic acid ester polymer (AE2) may contain a monomer unit (a3) derived from a monomer (a3m) having a functional group other than an organic acid group. Specific examples of the functional group other than the organic acid group are as described above, and a description thereof will be omitted. As the monomer (a3m) having a functional group other than the organic acid group, one type may be used alone, or two or more types may be used in combination. In the monomer (a3m) having a functional group other than these organic acid groups, the monomer unit (a3) derived therefrom is 10% by mass or less in the (meth) acrylate polymer (AE2). It is preferred to be used in the polymerization in such an amount. By using 10 mass% or less of monomer (a3m), the viscosity of the polymerization system at the time of polymerization can be maintained in an appropriate range.

  The (meth) acrylic acid ester polymer (AE2) has a (meth) acrylic acid ester monomer unit (a1) that forms a homopolymer having the above-described glass transition temperature of −20 ° C. or lower, and an organic acid group. In addition to the monomer unit (a2) and the monomer unit (a3) having a functional group other than an organic acid group, a monomer derived from the monomer (a4m) copolymerizable with the above-described monomer. The monomer unit (a4) may be contained. A monomer (a4m) may be used individually by 1 type, and may use 2 or more types together. The amount of the monomer unit (a4) derived from the monomer (a4m) is preferably 10% by mass or less, more preferably 5% by mass or less of the acrylate polymer (A1). Specific examples of the monomer (a4m) are as described above, and a description thereof is omitted.

  The weight average molecular weight (Mw) of the (meth) acrylic acid ester polymer (AE2) is measured by gel permeation chromatography (GPC method) and is in the range of 100,000 to 1,000,000 in terms of standard polystyrene. It is more preferable that it is in the range of 200,000 or more and 500,000 or less.

  The (meth) acrylic acid ester polymer (AE2) is a (meth) acrylic acid ester monomer (a1m), a monomer having an organic acid group, which forms a homopolymer having a glass transition temperature of −20 ° C. or lower. (A2m), a monomer containing a functional group other than an organic acid group (a3m) used as required, and a monomer copolymerizable with these monomers used as needed ( a4m) can be obtained particularly preferably by copolymerization.

  The polymerization method is not particularly limited, and the description can be omitted because it can be the same as the (meth) acrylic acid ester polymer (AE1) described above. After completion of the polymerization reaction, the obtained polymer is separated from the polymerization medium as necessary. The separation method is not particularly limited. In the case of solution polymerization, the (meth) acrylic acid ester polymer (AE2) can be obtained by placing the polymerization solution under reduced pressure and distilling off the polymerization solvent.

  The weight average molecular weight of the (meth) acrylic acid ester polymer (AE2) can be controlled by appropriately adjusting the amount of the polymerization initiator used in the polymerization and the amount of the chain transfer agent.

((Meth) acrylic acid ester monomer mixture (α2))
As the (meth) acrylic acid ester monomer mixture (α2) that can be used in the present invention, the same (meth) acrylic acid ester monomer mixture (α1) described above can be used. That is, the (meth) acrylic acid ester monomer mixture (α2) is mainly composed of a (meth) acrylic acid ester monomer (a5m) that forms a homopolymer having a glass transition temperature of −20 ° C. or lower. It contains a polyfunctional monomer (a6m). As described above, the above “main component” means “containing 50% by mass or more”.

  The (meth) acrylic acid ester monomer mixture (α2) is 90% by mass or more and 99.9% by mass or less of the (meth) acrylic acid ester monomer (a5m), and a polyfunctional monomer ( a6m) It is preferable that 0.1 mass% or more and 10 mass% or less are included. When the content ratio of the (meth) acrylic acid ester monomer (a5m) is 90% by mass or more and 99.9% by mass or less, a heat conductive pressure-sensitive adhesive composition excellent in pressure-sensitive adhesiveness and flexibility ( E) or a heat conductive pressure-sensitive adhesive sheet-like molded product (F) can be easily obtained.

  Specific examples of the (meth) acrylic acid ester monomer (a5m) forming a homopolymer having a glass transition temperature of −20 ° C. or lower are as described above, and a description thereof is omitted. The said (meth) acrylic acid ester monomer (a5m) may be used individually by 1 type, and may use 2 or more types together. Moreover, the specific example of a polyfunctional monomer (a6m) is also as above-mentioned, and description is abbreviate | omitted. A polyfunctional monomer (a6m) may be used individually by 1 type, and may use 2 or more types together.

  The (meth) acrylic acid ester monomer mixture (α2) is a monomer having an organic acid group that can be copolymerized with the (meth) acrylic acid ester monomer (a5m) or the polyfunctional monomer (a6m). It may contain a monomer (a7m). Examples of the monomer (a7m) having the organic acid group are as described above, and a description thereof is omitted. As the monomer having an organic acid group (a7m), one type may be used alone, or two or more types may be used in combination. The monomer (a7m) is preferably used in the polymerization in such an amount that it is 9.9% by mass or less in the (meth) acrylic acid ester monomer mixture (α2). By using a 9.9 mass% or less monomer (a7m), the viscosity of the mixed composition at the time of superposition | polymerization can be maintained in an appropriate range.

  In addition, the (meth) acrylic acid ester monomer mixture (α2) is another monomer copolymerizable with the above-described monomers contained in the (meth) acrylic acid ester monomer mixture (α2) ( a8m) may be contained. Examples of the monomer (a8m) are as described above, and a description thereof is omitted. A monomer (a8m) may be used individually by 1 type, and may use 2 or more types together. The monomer (a8m) is preferably used in the polymerization in such an amount that it is 9.9% by mass or less in the (meth) acrylic acid ester monomer mixture (α2). By using a 9.9 mass% or less monomer (a8m), the viscosity of the mixed composition at the time of superposition | polymerization can be maintained in an appropriate range.

<Polymerization initiator (C2)>
When the heat conductive pressure-sensitive adhesive composition (E) or the heat conductive pressure-sensitive adhesive sheet-like molded body (F) is molded, the (meth) acrylate monomer mixture (α2) contained therein is polymerized. To do. In order to accelerate the polymerization, the heat conductive pressure-sensitive adhesive composition (E) or the mixed composition constituting the heat conductive pressure-sensitive adhesive sheet-like molded body (F) contains a polymerization initiator (C2). ing.

  Examples of the polymerization initiator (C2) that can be used in the present invention include a photopolymerization initiator, an azo thermal polymerization initiator, an organic peroxide thermal polymerization initiator, and the like. From the viewpoint of the adhesive force of the composition (E) or the heat conductive pressure-sensitive adhesive sheet-like molded product (F), an organic peroxide thermal polymerization initiator is preferably used. Specific examples of the photopolymerization initiator, the azo thermal polymerization initiator, and the organic peroxide thermal polymerization initiator are the same as those that can be used as the polymerization initiator (C1), and thus the description thereof is omitted.

  The usage-amount of a polymerization initiator (C2) is 0.01 mass part or more and 10 mass parts or less with respect to 100 mass parts of (meth) acrylic resin compositions (A2). As for the minimum of the usage-amount of a polymerization initiator (C2), 0.1 mass part is preferable and 0.3 mass part is more preferable. On the other hand, the upper limit of the amount of the polymerization initiator (C2) used is preferably 5 parts by mass, more preferably 2 parts by mass. The polymerization conversion rate of the (meth) acrylic acid ester monomer mixture (α2) is preferably 95% by mass or more. By making the usage-amount of a polymerization initiator (C2) 0.01 mass part or more and 10 mass parts or less, the polymerization conversion rate of a (meth) acrylic acid ester monomer mixture ((alpha) 2) can be made into an appropriate range. . If the usage-amount of a polymerization initiator (C2) is less than 0.01 mass part, the polymerization conversion rate of a (meth) acrylic acid ester monomer mixture ((alpha) 2) will become low, and a heat conductive pressure sensitive adhesive composition ( E) or the monomer odor may remain in the heat conductive pressure-sensitive adhesive sheet-like molded product (F). Moreover, when the usage-amount of a polymerization initiator (C2) exceeds 10 mass parts, the thing of extremely low molecular weight will produce | generate in the polymer of a (meth) acrylic acid ester monomer mixture ((alpha) 2), and heat conduction will occur. There is a possibility that the shape of the pressure-sensitive adhesive sheet-like molded product (F) becomes unstable.

<Powdered composition (D)>
The heat conductive pressure-sensitive adhesive composition (E) and the heat conductive pressure-sensitive adhesive sheet-like molded body (F) of the present invention contain the above-described powder composition (D) of the present invention. By mixing the particulate composition (D) into the heat conductive pressure sensitive adhesive composition (E), or the composition constituting the heat conductive pressure sensitive adhesive sheet-like molded body (F), as described above, It is possible to suppress an increase in the viscosity of the composition, and in particular the thermal resistance in the thickness direction of the heat conductive pressure-sensitive adhesive composition (E) or the heat conductive pressure-sensitive adhesive sheet-like molded body (F). Can be reduced.

  Content of a granular composition (D) is 20 to 200 mass parts with respect to 100 mass parts of (meth) acrylic resin compositions (A2). 150 mass parts is preferable and, as for the upper limit of content of a granular composition (D), 100 mass parts is more preferable. On the other hand, the lower limit of the content of the granular composition (D) is preferably 25 parts by mass, and more preferably 30 parts by mass. By making content of a granular composition (D) into 20 mass parts or more and 200 mass parts or less, a heat conductive pressure sensitive adhesive composition (E) or a heat conductive pressure sensitive adhesive sheet-like molded object (F). It is easy to exhibit the effect of reducing the thermal resistance, and it becomes easy to mold the heat conductive pressure-sensitive adhesive composition (E) or the heat conductive pressure-sensitive adhesive sheet-like molded body (F).

<Others>
The heat conductive pressure-sensitive adhesive composition (E) and the heat conductive pressure-sensitive adhesive sheet-like molded product (F) of the present invention include at least the (meth) acrylic resin composition (A2) and the polymerization initiator (C2) described above. ) And the granular composition (D) may be contained in a predetermined ratio, and a known additive may be further added within a range not impeding the effects of the present invention. Known additives include phosphoric acid esters; foaming agents (including foaming aids); flame retardant thermally conductive inorganic compounds such as metal hydroxides and metal salt hydrates; glass fibers; expanded graphite powder; Thermally conductive inorganic compounds such as alumina and PITCH carbon fibers; external cross-linking agents; pigments such as carbon black and titanium dioxide; other fillers such as clay; nanoparticles such as fullerenes and carbon nanotubes; polyphenols, hydroquinones, And hindered amine-based antioxidants; thickeners such as acrylic polymer particles, fine silica, and magnesium oxide;

4). Production method of heat conductive pressure-sensitive adhesive composition (E) and heat conductive pressure-sensitive adhesive sheet-like molded body (F) The heat conductive pressure-sensitive adhesive composition (E) of the present invention is a material described so far. After mixing, the (meth) acrylic acid ester monomer mixture (α2) can be obtained by polymerization and crosslinking reaction.

  That is, the manufacturing method of the heat conductive pressure-sensitive adhesive composition (E) of the present invention is (meth) acrylic acid ester polymer (AE2) 5% by mass to 30% by mass, and the glass transition temperature is −20 ° C. (Meth) acrylate monomer mixture (α2) 70 mass% or more and 95 mass comprising a (meth) acrylic acid ester monomer as a main component and forming a polyfunctional monomer % (Meth) acrylic resin composition (A2) 100 parts by mass, granular composition (D) 20 parts by mass or more and 200 parts by mass or less, and polymerization initiator (C2) 0.01 parts by mass or more 10 A mixing step of mixing parts by mass or less, and a step of polymerizing and crosslinking the (meth) acrylic acid ester monomer mixture (α2) after the mixing step. In addition, the preferable content ratio of each material is as above-mentioned, and description is abbreviate | omitted. In addition, it is preferable to heat the polymerization and crosslinking reaction of the (meth) acrylic acid ester monomer mixture (α2). For the heating, for example, hot air, an electric heater, infrared rays, or the like can be used. The heating temperature at this time is preferably a temperature at which the polymerization initiator (C2) decomposes efficiently and the polymerization and crosslinking reaction of the (meth) acrylic acid ester monomer mixture (α2) proceeds. Although a temperature range changes with kinds of polymerization initiator (C2) to be used, 100 to 200 degreeC is preferable and 130 to 180 degreeC is more preferable.

  The heat conductive pressure-sensitive adhesive sheet-like molded product (F) of the present invention is prepared by mixing the materials described above into a sheet shape, or while forming into a sheet shape, while (meth) acrylic acid ester It can be obtained by polymerization and crosslinking reaction of the monomer mixture (α2).

  That is, the production method of the heat conductive pressure-sensitive adhesive sheet-like molded product (F) of the present invention is such that the (meth) acrylic acid ester polymer (AE2) is 5% by mass to 30% by mass and the glass transition temperature is − (Meth) acrylic acid ester monomer mixture (α2) 70 mass% or more comprising a (meth) acrylic acid ester monomer as a main component and forming a homopolymer having a temperature of 20 ° C. or lower. 95 parts by mass or less of (meth) acrylic resin composition (A2) 100 parts by mass, granular composition (D) 20 parts by mass or more and 200 parts by mass or less, and polymerization initiator (C2) 0.01 parts by mass The mixing step of mixing 10 parts by mass or less, and after forming the mixed composition obtained in the mixing step into a sheet shape, or while forming the mixed composition into a sheet shape (meta) Acrylic acid ester monomer mixture Polymerization and the step of performing a crosslinking reaction of ([alpha] 2), and a. In addition, the preferable content ratio of each material is as above-mentioned, and description is abbreviate | omitted. In addition, it is preferable to heat the polymerization and crosslinking reaction of the (meth) acrylic acid ester monomer mixture (α2). For the heating, for example, hot air, an electric heater, infrared rays, or the like can be used. The heating temperature at this time is preferably a temperature at which the polymerization initiator (C2) decomposes efficiently and the polymerization and crosslinking reaction of the (meth) acrylic acid ester monomer mixture (α2) proceeds. Although a temperature range changes with kinds of the polymerization initiator (C2) to be used, 100 to 200 degreeC is preferable and 130 to 180 degreeC is more preferable.

  The method for molding the mixed composition into a sheet is not particularly limited. For example, a casting method in which the mixed composition is applied onto a process paper such as a polyester film that has been subjected to a release treatment, and the mixed composition is sandwiched between two release-treated process papers, if necessary, and passed between rolls. Examples thereof include a method and a method of controlling the thickness through a die when the mixed composition is extruded using an extruder. Among them, a method of sandwiching the two processed papers between the peeled sheets and passing between the rolls, and a method of controlling the thickness through a die when extruding the mixed composition using an extruder are preferable. Even when a powder having a particle size close to or larger than the desired thickness of the thermally conductive pressure-sensitive adhesive sheet-like molded product (F) is present in the powder composition (D), the powder Forcibly crushing or destroying the large particle size portion of the granular composition (D) to make the thickness of the finally obtained thermally conductive pressure-sensitive adhesive sheet-like molded product (F) uniform. This is because it can. In particular, a method of sandwiching two process papers that have been peeled and passing them between rolls is more preferable because it is simple.

  The thickness of the heat conductive pressure-sensitive adhesive sheet-like molded product (F) is not particularly limited, but if the heat conductive pressure-sensitive adhesive sheet-shaped molded product (F) is thinned, the heat conductive pressure-sensitive adhesive sheet-shaped molded product ( Since the heat resistance of F) can be lowered, the thickness of the heat conductive pressure-sensitive adhesive sheet-like molded body (F) is preferably 3.0 mm or less, more preferably 2.0 mm or less. More preferably, it is 1.0 mm or less. On the other hand, from the viewpoint of preventing air from being involved when the heat conductive pressure-sensitive adhesive sheet-shaped molded body (F) is applied to a heating element or a heat radiating body, a heat conductive pressure-sensitive adhesive sheet-shaped molded body ( The thickness of F) is preferably 0.1 mm or more, more preferably 0.2 mm or more, and further preferably 0.5 mm or more.

  Moreover, a heat conductive pressure-sensitive-adhesive sheet-like molded object (F) can also be shape | molded on the single side | surface or both surfaces of a base material. The material which comprises the said base material is not specifically limited. Specific examples of the substrate include metals having excellent thermal conductivity such as aluminum, copper, stainless steel, and beryllium copper, and polymers having excellent thermal conductivity such as foils of alloys and thermally conductive silicone. And a sheet-like material made of the above, a heat-conductive plastic film containing a heat-conductive additive, various non-woven fabrics, a glass cloth, and a honeycomb structure. Plastic films include polyimide, polyethylene terephthalate, polyethylene naphthalate, polytetrafluoroethylene, polyether ketone, polyethersulfone, polymethylpentene, polyetherimide, polysulfone, polyphenylene sulfide, polyamideimide, polyesterimide, aromatic polyamide, etc. A film made of a heat-resistant polymer can be used.

5. Use example The heat conductive pressure-sensitive-adhesive composition (E) and heat conductive pressure-sensitive-adhesive sheet-like molded object (F) of this invention can be used as some electronic components. At that time, it can be directly molded on a base material such as a radiator and provided as a part of the electronic component. Specific examples of the electronic component include components around a heat generating part in a device having an electroluminescence (EL) light emitting diode (LED) light source, components around a power device such as an automobile, a fuel cell, a solar cell, a battery, and a mobile phone. And devices and parts having a heat generating part such as a personal digital assistant (PDA), a notebook computer, a liquid crystal, a surface conduction electron-emitting device display (SED), a plasma display panel (PDP), or an integrated circuit (IC). .

  In addition, as an example of the method of using the heat conductive pressure-sensitive adhesive composition (E) and the heat conductive pressure-sensitive adhesive sheet-like molded body (F) of the present invention for an electronic device, an LED light source is described below as a specific example. The usage method to do can be mentioned. That is, it is directly attached to the LED light source; sandwiched between the LED light source and the heat dissipation material (heat sink, fan, Peltier element, heat pipe, graphite sheet, etc.); The heat dissipation material connected to the LED light source (heat sink, fan, Peltier element) , Heat pipe, graphite sheet, etc.); used as a casing surrounding the LED light source; affixed to the casing surrounding the LED light source; and filling a gap between the LED light source and the casing. Application examples of LED light sources include backlight devices for display devices having a transmissive liquid crystal panel (TVs, mobile phones, PCs, notebook PCs, PDAs, etc.); vehicle lamps; industrial lighting; commercial lighting; Lighting; and the like.

  Specific examples other than the LED light source include the following. That is, PDP panel; IC heating part; Cold cathode tube (CCFL); Organic EL light source; Inorganic EL light source; High luminance light emitting LED light source; High luminance light emitting organic EL light source; And so on.

  Furthermore, as a usage method of the heat conductive pressure-sensitive-adhesive composition (E) and heat conductive pressure-sensitive-adhesive sheet-like molded object (F) of this invention, affixing on the housing | casing of an apparatus etc. can be mentioned. For example, in an apparatus used for an automobile or the like, it is affixed to the inside of a casing provided in the automobile; affixed to the outside of the casing provided in the automobile; a heat generating part (car navigation / A fuel cell / heat exchanger) and the casing; and affixing to a heat sink connected to a heat generating part (car navigation / fuel cell / heat exchanger) in the casing of the automobile; Can be mentioned.

  In addition to the automobile, the heat conductive pressure-sensitive adhesive composition (E) and the heat conductive pressure-sensitive adhesive sheet-like molded product (F) of the present invention can be used in the same manner. For example, personal computers; homes; TVs; mobile phones; vending machines; refrigerators; solar cells; surface-conduction electron-emitting device displays (SEDs); organic EL displays; inorganic EL displays; Organic EL display; laptop computer; PDA; fuel cell; semiconductor device; rice cooker; washing machine; washing dryer; optical semiconductor device combining optical semiconductor elements and phosphors; various power devices; Is mentioned.

  Furthermore, the heat conductive pressure-sensitive adhesive composition (E) and the heat conductive pressure-sensitive adhesive sheet-like molded product (F) of the present invention are not limited to the above-described usage methods, and may be used in other methods depending on the application. It is also possible to use it. For example, used for heat equalization of carpets and warm mats; used as LED light source / heat source sealant; used as solar cell sealant; used as solar cell backsheet Used between the backsheet of the solar cell and the roof; used inside the heat insulating layer inside the vending machine; used inside the housing of the organic EL lighting with a desiccant and a hygroscopic agent; organic EL lighting Use with desiccant and hygroscopic agent on the heat conductive layer inside the housing of the LED; Use with desiccant and hygroscopic agent on the heat conductive layer and heat dissipation layer inside the housing of the organic EL lighting Used for heat conduction layer inside the housing of organic EL lighting, epoxy heat dissipation layer, and on top of it with desiccant and hygroscopic agent; cooling equipment, clothing, towels, sheets, etc. for cooling humans and animals On the opposite side of the body to the member Used for a pressure member of a fixing device mounted on an image forming apparatus such as an electrophotographic copying machine or an electrophotographic printer; Pressurizing a fixing device mounted on an image forming apparatus such as an electrophotographic copying machine or an electrophotographic printer Used as a member itself; used as a heat flow control heat transfer part for placing a treatment object of a membrane control device; used as a heat flow control heat transfer part for placing a treatment object of a film control device; outer layer of a radioactive substance storage container It can be used between the interior and interior; used in a box body with a solar panel that absorbs sunlight; used between the reflective sheet of the CCFL backlight and the aluminum chassis.

  Hereinafter, the present invention will be described in more detail by way of examples. However, the present invention is not limited to the examples. The “parts” and “%” used here are based on mass unless otherwise specified.

<Manufacture of a granular composition>
The granular composition concerning Examples 1-4 and Comparative Examples 1-3 was manufactured by the method demonstrated below using the substance shown in Table 1. FIG. In addition, the mixture ratio of each substance shown in Table 1 is shown by "mass part".

Example 1
A reactor was charged with 100 parts of a monomer mixture composed of 94% 2-ethylhexyl acrylate and 6% acrylic acid, 0.03 parts 2,2′-azobisisobutyronitrile and 700 parts ethyl acetate. Then, after substitution with nitrogen, a polymerization reaction was carried out at 80 ° C. for 6 hours. The polymerization conversion rate was 97%. The obtained polymer was dried under reduced pressure to evaporate ethyl acetate to obtain a viscous solid (meth) acrylic acid ester polymer (AE1-1). The (meth) acrylic acid ester polymer (AE1-1) had a weight average molecular weight (Mw) of 270,000 and a weight average molecular weight (Mw) / number average molecular weight (Mn) of 3.1. The weight average molecular weight (Mw) and the number average molecular weight (Mn) were determined in terms of standard polystyrene by gel permeation chromatography using tetrahydrofuran as an eluent.

  Next, as the (meth) acrylic acid ester monomer mixture (α1-1), a polyfunctional monomer obtained by mixing pentaerythritol triacrylate, pentaerythritol tetraacrylate and pentaerythritol diacrylate in a ratio of 60: 35: 5. 1 part, 89 parts of 2-ethylhexyl acrylate (hereinafter abbreviated as “2EHA”), 1,6-bis (t-butylperoxycarbonyloxy) hexane (half-minute for 1 minute) as a polymerization initiator (C1) The initial temperature is 150 ° C.) 1 part was weighed with an electronic balance, and these were mixed with 10 parts of the (meth) acrylic acid ester polymer (AE1-1). For the mixing, a thermostatic bath (manufactured by Toki Sangyo Co., Ltd., trade name “Viscomate 150III”) and Hobart mixer (manufactured by Kodaira Seisakusho, trade name “ACM-5LVT type”, capacity: 5 L) were used. The temperature control of the Hobart container was set to 60 ° C. and stirred for 10 minutes. This process is referred to as a first mixing process.

  Next, 300 parts of expanded graphite powder (trade name: EC-500, average particle size: 30 μm, manufactured by Ito Graphite Industries Co., Ltd.) is weighed and put into the Hobart container, and the temperature control of the Hobart container is adjusted to 60 ° C. Set and stir for 30 minutes. This process is referred to as a second mixing process.

  Thereafter, the mixed composition obtained through the first and second mixing steps was transferred to an aluminum container, placed in an oven, and heated at 150 ° C. for 15 minutes. By this heating step, the (meth) acrylic acid ester monomer mixture (α1-1) was polymerized and crosslinked to obtain a lump. This was manually pulverized using a bar to reduce the particle size of all the particles to less than 500 μm, and a granular composition (D-1) according to Example 1 was obtained.

(Example 2, Example 4, and Example 5)
The granular composition according to Example 2, Example 4 and Example 5 in the same manner as in Example 1 except that the substances to be mixed in the second mixing step and the blending amount thereof were changed as shown in Table 1. (D-2, D-4, D-5) were obtained. In Example 2 and Example 4, expanded graphite powder (manufactured by Ito Graphite Industry Co., Ltd., trade name: EC-1500, average particle size: 3 μm) was used. In Example 5, expanded graphite powder was used. (Product name: EC-500, average particle size: 30 μm, manufactured by Ito Graphite Industries Co., Ltd.) was used.

(Example 3)
In the first mixing step, Example 3 was applied in the same manner as Example 1 except that the blending amounts of 2EHA and (meth) acrylic acid ester polymer (AE1-1) were changed as shown in Table 1. A granular composition (D-3) was obtained.

(Comparative Example 1)
In the first mixing step, as shown in Table 1, the granular composition (DC-) according to Comparative Example 1 was used in the same manner as in Example 1 except that the polyfunctional monomer (crosslinking agent) was not used. 1) was obtained.

(Comparative Example 2)
In the second mixing step, as shown in Table 1, in place of 300 parts of expanded graphite powder (EC-500), spherical graphite (trade name: SG-BL30, manufactured by Ito Graphite Industries Co., Ltd., average particle size: 30 μm) ) A bulk composition (DC-2) according to Comparative Example 2 was obtained in the same manner as in Example 1 except that 300 parts were blended.

(Comparative Example 3)
As shown in Table 1, in the second mixing step, the same procedure as in Comparative Example 1 was conducted except that 700 parts of expanded graphite powder (EC-1500) was blended instead of 300 parts of expanded graphite powder (EC-500). Thus, a bulk composition (DC-3) according to Comparative Example 3 was obtained.

(Comparative Example 4)
As shown in Table 1, in the second mixing step, the same procedure as in Comparative Example 1 was conducted except that 50 parts of expanded graphite powder (EC-500) was blended instead of 300 parts of expanded graphite powder (EC-500). Thus, a bulk composition (DC-4) according to Comparative Example 4 was obtained.

  As will be described below, when the granular composition (D-1 to D-5) according to the examples is used, a thermally conductive pressure-sensitive adhesive sheet-like molded article having good productivity and low thermal resistance is obtained. It was. On the other hand, when the powdered granular composition (DC-1 to DC-4) according to the comparative example is used, the productivity of the heat conductive pressure-sensitive adhesive sheet-like molded product is poor, and the heat conductive pressure-sensitive adhesive sheet-like molding. The body's thermal resistance was high.

<Preparation of heat conductive pressure-sensitive adhesive sheet-like molded body>
The heat conductive pressure-sensitive-adhesive sheet-like molded object concerning Example A-Example H and Comparative Example A-Comparative Example E was manufactured by the method demonstrated below using the substance shown in Table 2. FIG. The “productivity” and “cool-down effect” shown in Table 2 were evaluated by the methods described below.

(productivity)
The fluidity of the mixed composition obtained through the third to fifth mixing steps described below was evaluated. When the mixed composition has fluidity, the productivity of the heat conductive pressure-sensitive adhesive sheet-like molded body is higher. The Hobart container in which the mixed composition was placed was tilted by 30 ° with respect to the horizontal plane, and the case where the mixed composition flowed was “◯”, and the case where it did not move was “x”.

(Cooldown effect)
The heat conductive pressure-sensitive adhesive sheet-like molded body was cut into a size of 25 mm × 25 mm. The heat conductive pressure-sensitive adhesive sheet-like molded product is attached to an aluminum plate of 150 mm × 150 mm × thickness 3 mm, and the side of the heat conductive pressure-sensitive adhesive sheet-like molded product opposite to the side attached to the aluminum plate On the surface, a micro ceramic heater (manufactured by Sakaguchi Electric Heat Co., Ltd., trade name: MS-5, 25 mm × 25 mm) was fixed with double-sided tape, and the aluminum plate was suspended. Thereafter, a micro ceramic heater was connected to the slidac, and the surface of the micro ceramic heater when heated at 60 W for 60 minutes was photographed by thermography. The maximum temperature at that time is shown in Table 2. The lower the temperature means that more heat is transferred from the micro ceramic heater to the aluminum plate, so the lower the temperature, the lower the thermal resistance of the heat conductive pressure-sensitive adhesive sheet-like molded body. It can be said. This evaluation was performed in an atmosphere at 23 ° C.

(Example A)
(Meth) acrylic acid ester polymer, (meth) acrylic acid ester monomer mixture, and polymerization initiator similar to those used in the first mixing step of Example 1, and aluminum hydroxide (Nippon Light Metal Co., Ltd.) Manufactured, product name: BF083) 300 parts. For the mixing, a thermostatic bath (manufactured by Toki Sangyo Co., Ltd., trade name “Viscomate 150III”) and Hobart mixer (manufactured by Kodaira Seisakusho, trade name “ACM-5LVT type”, capacity: 5 L) were used. The temperature control of the Hobart container was set to 60 ° C. and stirred for 10 minutes. This process is referred to as a third mixing process.

  Next, 50 parts of the granular composition (D-1) according to Example 1 was weighed and put into the Hobart container, and the temperature control of the Hobart container was set to 60 ° C. and stirred for 10 minutes. This process is referred to as a fourth mixing process.

  Thereafter, the inside of the Hobart container was evacuated, the temperature control of the Hobart container was set to 60 ° C., and the mixture was stirred for 5 minutes. This process is referred to as a fifth mixing process.

  Next, the mixture composition obtained through the third to fifth mixing steps is hung on a polyethylene terephthalate film (hereinafter referred to as “release PET film”) having a thickness of 50 μm, which has been subjected to a release treatment. A release PET film having a thickness of 50 μm was further covered on the mixed composition. This laminated body in which the mixed composition was sandwiched between release PET films was passed through a roll having a distance of 0.6 mm between them to form a sheet. Thereafter, the laminate was put into an oven and heated at 150 ° C. for 15 minutes. By this heating step, the (meth) acrylic acid ester monomer mixture contained in the mixed composition was polymerized and crosslinked. Thereafter, the release PET film attached to both surfaces was peeled off to obtain a heat conductive pressure-sensitive adhesive sheet-like molded body (hereinafter simply referred to as “sheet”) having a thickness of 0.5 mm. The polymerization conversion rate of the (meth) acrylic acid ester monomer mixture was calculated from the amount of residual monomers in the sheet and found to be 99.9%.

(Example B to Example E, Example H, and Comparative Example A to Comparative Example E)
Example B to Example E, Example H, and Comparative Example A to Comparative Example except that the substances to be mixed in the fourth mixing step and the blending amounts thereof were changed as shown in Table 2 in the same manner as Example A A sheet according to Example E was obtained.

(Example F)
A sheet according to Example F was obtained in the same manner as Example E except that aluminum hydroxide was not used in the third mixing step.

(Example G)
In the third mixing step, Example G was carried out in the same manner as Example A except that 300 parts of spherical alumina (manufactured by Denki Kagaku Kogyo Co., Ltd., trade name: DAM-45) was used instead of 300 parts of aluminum hydroxide. Such a sheet was obtained.

  As shown in Table 2, all the sheets according to the examples had good productivity and low thermal resistance. On the other hand, the sheets according to the comparative examples all had poor productivity and high thermal resistance.

Claims (8)

(Meth) acrylic acid ester polymer (AE1) 5 mass% or more and 70 mass% or less, and (meth) acrylic acid ester monomer that forms a homopolymer having a glass transition temperature of −20 ° C. or lower as a main component And (meth) acrylic acid ester monomer mixture (α1) containing 30% by mass to 95% by mass including a polyfunctional monomer, and 100 parts by mass of (meth) acrylic resin composition (A1),
100 parts by mass or more and 650 parts by mass or less of expanded graphite powder (B) having an average particle size of 2 μm or more and less than 60 μm,
Polymerization initiator (C1) 0.01 parts by weight or more and 10 parts by weight or less;
The granular composition (D) formed by grind | pulverizing the block composition by which superposition | polymerization and crosslinking reaction of the said (meth) acrylic acid ester monomer mixture ((alpha) 1) in the mixed composition containing this are performed.   The (meth) acrylic acid ester monomer mixture (α1) is 90% by mass or more and 99.9% by mass or less of the (meth) acrylic acid ester monomer, and 0.1% by mass of the polyfunctional monomer. The granular composition (D) according to claim 1, comprising from 10% to 10% by mass. (Meth) acrylic acid ester polymer (AE2) 5 mass% or more and 30 mass% or less, and (meth) acrylic acid ester monomer that forms a homopolymer having a glass transition temperature of −20 ° C. or lower as a main component And (meth) acrylic acid ester monomer mixture (α2) containing 70% by mass to 95% by mass containing a polyfunctional monomer, and 100 parts by mass of (meth) acrylic resin composition (A2),
20 to 200 parts by mass of the granular composition (D) according to claim 1 or 2,
Polymerization initiator (C2) 0.01 parts by weight or more and 10 parts by weight or less;
Thermally conductive pressure-sensitive adhesive composition (E) obtained by polymerization and crosslinking reaction of the (meth) acrylic acid ester monomer mixture (α2) in a mixed composition comprising: (Meth) acrylic acid ester polymer (AE2) 5 mass% or more and 30 mass% or less, and (meth) acrylic acid ester monomer that forms a homopolymer having a glass transition temperature of −20 ° C. or lower as a main component And (meth) acrylic acid ester monomer mixture (α2) containing 70% by mass to 95% by mass containing a polyfunctional monomer, and 100 parts by mass of (meth) acrylic resin composition (A2),
20 to 200 parts by mass of the granular composition (D) according to claim 1 or 2,
Polymerization initiator (C2) 0.01 parts by weight or more and 10 parts by weight or less;
Polymerization of the (meth) acrylic acid ester monomer mixture (α2) and a crosslinking reaction are performed after the mixed composition containing is molded into a sheet or while the mixed composition is molded into a sheet Thermally conductive pressure-sensitive adhesive sheet-like molded product (F). (Meth) acrylic acid ester polymer (AE1) 5 mass% or more and 70 mass% or less, and (meth) acrylic acid ester monomer that forms a homopolymer having a glass transition temperature of −20 ° C. or lower as a main component And (meth) acrylic acid ester monomer mixture (α1) containing 30% by mass to 95% by mass including a polyfunctional monomer, and 100 parts by mass of (meth) acrylic resin composition (A1),
100 parts by mass or more and 650 parts by mass or less of expanded graphite powder (B) having an average particle size of 2 μm or more and less than 60 μm,
Polymerization initiator (C1) 0.01 parts by weight or more and 10 parts by weight or less;
Mixing process,
After the mixing step, the step of polymerizing and crosslinking the (meth) acrylic acid ester monomer mixture (α1) to obtain a bulk composition, and
Crushing the massive composition into a powder,
The manufacturing method of a granular composition (D) containing this. (Meth) acrylic acid ester polymer (AE2) 5 mass% or more and 30 mass% or less, and (meth) acrylic acid ester monomer that forms a homopolymer having a glass transition temperature of −20 ° C. or lower as a main component And (meth) acrylic acid ester monomer mixture (α2) containing 70% by mass to 95% by mass containing a polyfunctional monomer, and 100 parts by mass of (meth) acrylic resin composition (A2),
20 to 200 parts by mass of the granular composition (D) according to claim 1 or 2,
Polymerization initiator (C2) 0.01 parts by weight or more and 10 parts by weight or less;
Mixing step of preparing a mixed composition, and
A step of polymerizing and crosslinking reaction of the (meth) acrylic acid ester monomer mixture (α2) after the mixing step;
The manufacturing method of a heat conductive pressure-sensitive-adhesive composition (E) containing this. (Meth) acrylic acid ester polymer (AE2) 5 mass% or more and 30 mass% or less, and (meth) acrylic acid ester monomer that forms a homopolymer having a glass transition temperature of −20 ° C. or lower as a main component And (meth) acrylic acid ester monomer mixture (α2) containing 70% by mass to 95% by mass containing a polyfunctional monomer, and 100 parts by mass of (meth) acrylic resin composition (A2),
20 to 200 parts by mass of the granular composition (D) according to claim 1 or 2,
Polymerization initiator (C2) 0.01 parts by weight or more and 10 parts by weight or less;
Mixing step of preparing a mixed composition, and
Polymerization and crosslinking of the (meth) acrylic acid ester monomer mixture (α2) after forming the mixed composition obtained in the mixing step into a sheet or while forming the mixed composition into a sheet Carrying out the reaction,
The manufacturing method of the heat conductive pressure-sensitive-adhesive sheet-like molded object (F) containing.   The heat conductive pressure-sensitive adhesive composition (E) according to claim 3 bonded to the heat radiator and the heat radiator, or the heat according to claim 4 bonded to the heat radiator and the heat radiator. An electronic component comprising a conductive pressure-sensitive adhesive sheet-like molded body (F).